a b Pessarakli, Mohammad (2005). Handbook of Photosynthesis. CRC Press. pp.717–739. ISBN 978-0-8247-5839-4. Archived from the original on 21 May 2016 . Retrieved 28 February 2016. Consequently, from both a taxonomic and a phylogenetic perspective, the tree is an artificial category. On an ecological basis, however, the tree can be recognized as a natural construct, as it represents an adaptive strategy by many different taxa to exploit and dominate the habitat above the ground. Tanneries, Description of the Tanning Process". Food and Agriculture Organization of the United Nations. Archived from the original on 22 August 2011 . Retrieved 26 July 2012. Koch, George W.; Sillett, Stephen C.; Jennings, Gregory M.; Davis, Stephen D. (22 April 2004). "The limits to tree height". Nature. 428 (6985): 851–854. Bibcode: 2004Natur.428..851K. doi: 10.1038/nature02417. PMID 15103376. S2CID 11846291. Women watch: International Day of Rural Women". United Nations Inter-agency Network on Women and Gender Equality. 15 October 2008. Archived from the original on 17 December 2011 . Retrieved 1 August 2012.

Hawthorne, William; Lawrence, Anna (2012). Plant Identification: Creating User-Friendly Field Guides for Biodiversity Management. Routledge. p.138. ISBN 978-1-84407-079-4. Archived from the original on 7 February 2017 . Retrieved 28 February 2016. The tropical rain forest". Biomes of the World. Marietta College. Archived from the original on 23 May 2011 . Retrieved 28 July 2012. To many, the word tree evokes images of such ancient, powerful, and majestic structures as oaks and sequoias, the latter being among the most massive and longest-living organisms in the world. Although the majority of Earth’s terrestrial biomass is represented by trees, the fundamental importance of these seemingly ubiquitous plants for the very existence and diversity of life on Earth is perhaps not fully appreciated. The biosphere is dependent on the metabolism, death, and recycling of plants, especially trees. Their vast trunks and root systems store carbon dioxide, move water, and produce oxygen that is released into the atmosphere. The organic matter of the soil develops primarily from decayed leaves, twigs, branches, roots, and fallen trees, all of which recycle nitrogen, carbon, oxygen, and other important nutrients. There are few organisms as important as trees for maintaining Earth’s ecology. Amos, Jonathan (3 September 2015). "Earth's trees number 'three trillion' ". BBC News. Archived from the original on 19 July 2019 . Retrieved 3 September 2015.When growing conditions improve, such as the arrival of warmer weather and the longer days associated with spring in temperate regions, growth starts again. The expanding shoot pushes its way out, shedding the scales in the process. These leave behind scars on the surface of the twig. The whole year's growth may take place in just a few weeks. The new stem is unlignified at first and may be green and downy. The Arecaceae (palms) have their leaves spirally arranged on an unbranched trunk. [72] In some tree species in temperate climates, a second spurt of growth, a Lammas growth may occur which is believed to be a strategy to compensate for loss of early foliage to insect predators. [73] Walnuts are the healthiest nut, say scientists". BBC News: Health. 28 March 2011. Archived from the original on 24 September 2017 . Retrieved 21 September 2014. Guidelines for the treatment of malaria" (PDF). World Health Organization. 2006. Archived (PDF) from the original on 13 October 2015 . Retrieved 26 July 2012.

Many trees have flowers rich in nectar which are attractive to bees. The production of forest honey is an important industry in rural areas of the developing world where it is undertaken by small-scale beekeepers using traditional methods. [117] The flowers of the elder ( Sambucus) are used to make elderflower cordial and petals of the plum ( Prunus spp.) can be candied. [118] Sassafras oil is a flavouring obtained from distilling bark from the roots of the sassafras tree ( Sassafras albidum). Saplings" redirects here. For the novel, see Saplings (novel). For the film, see The Saplings. For the episode, see Saplings (Weeds). Trees have been venerated since time immemorial. To the ancient Celts, certain trees, especially the oak, ash and thorn, held special significance [158] as providing fuel, building materials, ornamental objects and weaponry. Other cultures have similarly revered trees, often linking the lives and fortunes of individuals to them or using them as oracles. In Greek mythology, dryads were believed to be shy nymphs who inhabited trees. Dead trees pose a safety risk, especially during high winds and severe storms, and removing dead trees involves a financial burden, whereas the presence of healthy trees can clean the air, increase property values, and reduce the temperature of the built environment and thereby reduce building cooling costs. During times of drought, trees can fall into water stress, which may cause a tree to become more susceptible to disease and insect problems, and ultimately may lead to a tree's death. Irrigating trees during dry periods can reduce the risk of water stress and death. [156] Conservation

Young trees need water to survive

Baluška, František; Mancuso, Stefano (2009). Signaling in Plants. Springer. pp.83–84. ISBN 978-3-540-89227-4. Archived from the original on 19 August 2020 . Retrieved 29 May 2020. At least 120 drugs come from plant sources, many of them from the bark of trees. [142] Quinine originates from the cinchona tree ( Cinchona) and was for a long time the remedy of choice for the treatment of malaria. [143] Aspirin was synthesised to replace the sodium salicylate derived from the bark of willow trees ( Salix) which had unpleasant side effects. [144] The anti-cancer drug Paclitaxel is derived from taxol, a substance found in the bark of the Pacific yew ( Taxus brevifolia). [145] Other tree based drugs come from the paw-paw ( Carica papaya), the cassia ( Cassia spp.), the cocoa tree ( Theobroma cacao), the tree of life ( Camptotheca acuminata) and the downy birch ( Betula pubescens). [142]

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a b Taylor, Leslie (13 October 2000). "Plant Based Drugs and Medicines". The Healing Power of Rainforest Herbs. Archived from the original on 29 June 2012 . Retrieved 27 July 2012. Koch, George W.; Sillett, Stephen C.; Jennings, Gregory M.; Davis, Stephen D. (2004). "The limits to tree height" (PDF). Letters to Nature. Nature Publishing Group. 428 (6985): 851–4. Bibcode: 2004Natur.428..851K. doi: 10.1038/nature02417. PMID 15103376. S2CID 11846291. Archived from the original (PDF) on 21 October 2012 . Retrieved 18 December 2021. Eastern Australia Temperate Forest". WWF. Archived from the original on 10 September 2014 . Retrieved 10 September 2014. Ruxton, Graeme D.; Schaefer, H. Martin (2012). "The conservation physiology of seed dispersal". Philosophical Transactions of the Royal Society. 367 (1596): 1708–1718. doi: 10.1098/rstb.2012.0001. PMC 3350653. PMID 22566677. Nathan, Ran; Seidler, Tristram G.; Plotkin, Joshua B. (2006). "Seed Dispersal and Spatial Pattern in Tropical Trees". PLOS Biology. 4 (11): e344. doi: 10.1371/journal.pbio.0040344. PMC 1609130. PMID 17048988. {{ cite journal}}: CS1 maint: unflagged free DOI ( link)

Word History

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